ORIGINAL ARTICLE Growth pattern of serous cystic neoplasms of the pancreas: observational study with long-term magnetic resonance surveillance and recommendations for treatment Giuseppe Malleo, 1 Claudio Bassi, 1 Roberto Rossini, 1 Riccardo Manfredi, 2 Giovanni Butturini, 1 Marta Massignani, 1 Marina Paini, 1 Paolo Pederzoli, 1 Roberto Salvia 1 ABSTRACT Background and aims The natural history and growth pattern of pancreatic serous cystic neoplasms (SCNs) are not well understood. This study was designed in order to get insight into the growth rate of SCNs and to suggest recommendations for their management. Methods Patients with well-documented incidentally discovered or minimally symptomatic SCNs who underwent yearly surveillance MRI were analysed using a linear mixed model. The growth rate and the effects of different fixed factors (sex, personal history of other non- pancreatic malignancies, radiological pattern, clinical presentation, tumour site) and random factors (age and tumour diameter at the time of diagnosis) on tumour growth were investigated. Results Study population consisted of 145 patients. Estimated overall mean growth rate was 0.28 cm/year, but the growth curve analysis showed a different trend between the first 7 years after the baseline evaluation (growth rate of 0.1 cm/year) and the subsequent period (years 7 to 10, growth rate of 0.6 cm/year, p<0.0001). Tests for fixed effects demonstrated that an oligocystic/ macrocystic pattern and a personal history of other tumours are significant predictors of a more rapid mean tumour growth (p<0.0001 and 0.022, growth rates of 0.34 cm/year). Furthermore, tumour growth significantly increased with age (p¼0.0001). Conclusion Overall, SCNs grow slowly, and an initial non-operative approach is feasible in all the asymptomatic or minimally symptomatic patients. The oligocystic/macrocystic variant, a history of other non- pancreatic malignancies and patients’ age impact on tumour growth. In any case, a significant growth is unlikely to occur before 7 years from the baseline evaluation. Tumour size at the time of diagnosis should not be used for decisional purposes. INTRODUCTION In the last 2 decades, there has been an increased awareness of serous cystic neoplasms of the pancreas (SCNs), mainly due to the widespread use of cross-sectional imaging. 12 These lesions are virtually always benign neoplasms, but local growth can result in abdominal symptoms. 3e5 The principal diagnostic effort is directed towards differentiating SCNs from the potentially malig- nant mucin-producing lesions (such as mucinous cystic neoplasms and intraductal papillary mucinous neoplasms (IPMNs)). Radiological char- acteristics that may help to identify SCNs include the presence of multiple cysts measuring 2 cm or smaller separated by fibrous septa that may < Additional materials are published online only. To view these files please visit the journal online (http://gut.bmj. com). 1 Department of Surgery, Unit of General Surgery B, ‘G.B. Rossi’ Hospital, University of Verona, Verona, Italy 2 Department of Radiology, Unit of Radiology, University of Verona, Verona, Italy Correspondence to Dr Roberto Salvia, Department of Surgery, General Surgery B, ‘G.B. Rossi’ Hospital, P.le L.A. Scuro 10, 37134 Verona, Italy; roberto.salvia@ ospedaleuniverona.it The results of this paper have been presented in partial form at the 45th Annual Pancreas Club Meeting, Chicago, Illinois, USA, May 6e7, 2011. Revised 20 July 2011 Accepted 21 July 2011 Significance of this study What is already known about this subject? < Serous cystic neoplasms of the pancreas should be resected when symptomatic or in case of an unclear differential diagnosis with mucin- producing tumours. < It has been proposed that asymptomatic lesions larger than 4 centimeters should be also resected (in surgically fit patients) because of a very rapid growth rate. < Small asymptomatic lesions can be observed with periodic imaging. What are the new findings? < Serous cystic neoplasms of the pancreas grow slower than previously thought. < A significant growth is unlikely to occur before 7 years from the baseline evaluation. < Maximum diameter at the time of diagnosis is not a predictor of tumour growth. < Macrocystic pattern, a history of other non- pancreatic malignancies and age are significant predictors of tumour growth. How might it impact on clinical practice in the foreseeable future? < Asymptomatic or minimally symptomatic serous cystic neoplasms larger than 4 cm can be safely managed by the same periodic surveillance protocol. < Patients presenting with factors that impact on tumour growth are more likely to require resection at the long term. < Semiannual or annual follow-up is not necessary for asymptomatic or minimally symptomatic neoplasms; a time frame of at least 2 years seems appropriate. Malleo G, Bassi C, Rossini R, et al. Gut (2011). doi:10.1136/gutjnl-2011-300297 1 of 6 Pancreas Gut Online First, published on September 22, 2011 as 10.1136/gutjnl-2011-300297 Copyright Article author (or their employer) 2011. Produced by BMJ Publishing Group Ltd (& BSG) under licence. group.bmj.com on September 26, 2011 - Published by gut.bmj.com Downloaded from